title: Ikarugamycin induces DNA damage, intracellular calcium increase, p38 MAP kinase activation and apoptosis in HL-60 human promyelocytic leukemia cells.
abstract: Ikarugamycin (IKA) is an antibiotic with strong antiprotozoal and cytotoxic activity. The purpose of our work was to provide insight into the mechanism of action characterizing the cytotoxic effect of IKA in HL-60 leukemia cells in order to evaluate its potential as an antineoplastic agent. Cell viability was reduced in response to IKA (IC(50) of 221.3nM), while the amount of HL-60 cells with a subdiploid DNA content increased significantly after 24h. Apoptotic cell death was confirmed by the cleavage of caspase-9, -8 and -3 using immunoblotting. Single cell gel electrophoresis pointed to an early genotoxic effect. Monitoring of intracellular calcium ([Ca(2+)](i)) levels by flow cytometric analysis of Fluo-3-AM fluorescence indicated an increase in cytosolic calcium that correlated with the cleavage of caspases. In addition, IKA triggered the activation of p38 MAP kinase which was partly dependent on elevated [Ca(2+)](i) concentrations and contributed to caspase activation. The data demonstrate that IKA induced apoptosis in HL-60 cells through genotoxicity and caspase activation which was in part correlated to an increase in intracellular calcium levels and activation of p38 MAP kinase.
authors.affiliation: Department of Pharmacognosy, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.
authors.forename: Ruxandra
authors.initials: R
authors.lastname: Popescu
authors.forename: Elke Hannelore
authors.initials: EH
authors.lastname: Heiss
authors.forename: Franziska
authors.initials: F
authors.lastname: Ferk
authors.forename: Andrea
authors.initials: A
authors.lastname: Peschel
authors.forename: Siegfried
authors.initials: S
authors.lastname: Knasmueller
authors.forename: Verena Maria
authors.initials: VM
authors.lastname: Dirsch
authors.forename: Georg
authors.initials: G
authors.lastname: Krupitza
authors.forename: Brigitte
authors.initials: B
authors.lastname: Kopp
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D004249:DNA Damage / Q000187:drug effects*; D018922:HL-60 Cells; D006801:Humans; D007769:Lactams / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000096:biosynthesis*
chemical_list: D000970:Antineoplastic Agents; D007769:Lactams; C074292:ikarugamycin; D048051:p38 Mitogen-Activated Protein Kinases; D002118:Calcium